Step-by-step explanation:
The Pioneer plaques were gold plated plaques sent on the Pioneer 10 and 11. These spacecrafts were designed to travel out of the solar system. The purpose of these plaques was to give the information about life on Earth, position of Sun and Solar system in the Galaxy etc. to anyone who happens to find these in space. The information was to be conveyed in such a language that any extra terrestrial intelligent life would be able to understand it. These units might not be familiar with societies on Earth.